Do not try to write your business plan in one sitting. As I mentioned in the beginning, for a traditional brick and mortar business, it could take in excess of 100 hours to compile all of the information needed into a comprehensive but yet understandable document. For online businesses, probably not that long. But your final product should be well thought out, well documented and easily understandable.
A plan should include but is not limited to the following: 1. A statement of your business purpose 2. A description of your company 3. The goals of your company 4. The structure of the company (sole_proprietorship, partnership or corporation) 5. The product or service that you are selling 6. A market analysis of your product or service 7. Resources spent (time and money) 8. A financial plan to include financial statements 9. Information about the managing principals in the company 10. How you plan to manage and operate the company